As genealogists we begin our research with what we know and work backwards. That, and the fact that privacy is not as much of an issue, make death records one of the best places to begin an online search for information. Whether it's a death certificate, obituary notice, or tombstone photo, death records offer a decent chance for locating information about our ancestor and/or the people he associated with. To get you started, here are 10 Places to Start Your Search for Online Death Records - some of them free, and some pay-per-view or subscription.
I often get asked "Why should I look for a death record? I already know when my ancestor died." There are so many other things you can learn from death records beyond the date of death. Names are a big one - the name of the spouse, parents, informant (often a family member, such as a child or son/daughter-in-law), undertaker, doctor, etc. These are all new people we can research in our quest for information. There are also the occupation and the place of burial which can lead to new avenues of research. Even the cause of death might open doors to newspaper reports of an accident, or records of a coroner's inquest.
Do you have death information for all of the individuals in your family tree? Especially the more recent generations? We often first locate information about an ancestor in a census, or similar record, and then excitedly start working backward from there to the previous generation. Just don't so excited that you forget to research his entire life - from birth to death.